Abstract: In order to explore the characteristics of aerosol vertical distribution and the influence of meteorological elements in typical haze processes in Xi'an City, the ground air quality, CALIPSO satellite and meteorological data and the HYSPLIT backward trajectory model, synoptic situation analysis and correlation analysis were used in this study. Based on the relative humidity (RH), the haze episode of Xi'an City from December 17^th to 21^st was divided into dry haze, wet haze and fog-haze, and the vertical distribution characteristics of aerosol at different stages were analyzed. The study showed that in addition to the dust transported from the northwest region, dust aerosols with large depolarization ratio and color ratio played a dominant role in the early dry haze stage. More fine particles were generated by the increasing RH in wet haze in the middle stage, when the extinction coefficient reached 1.7 km^-1, and the pollution aerosols played the dominant role instead. Then, mixtures of pollutants and dust were observed and coarse particles accumulated close to the ground when RH decreased in the later dry haze stage. Breeze, high humidity and double temperature inversion combined to increase pollutants, and the change in the temperature inversion intensity had a certain lag consistency with the growth and decline of pollutants. The visibility was dominated by relative humidity when RH was higher than 80%, with a correlation coefficient reaching -0.871. The particle concentration played a leading role when the RH was lower than 80%, and the correlation coefficient was more than 0.85. Besides, the vertical distribution characteristics of aerosol in different haze stages were quite different, and meteorological factors had an important influence on the haze process.